UG/Abi: a highly diverse family of prokaryotic reverse transcriptases associated with defense functions

Reverse transcriptases (RTs) are enzymes capable of synthesizing DNA using RNA as a template. Within the last few years, a burst of research has led to the discovery of novel prokaryotic RTs with diverse antiviral properties, such as DRTs (Defense-associated RTs), which belong to the so-called group of unknown RTs (UG) and are closely related to the Abortive Infection system (Abi) RTs. In this work, we performed a systematic analysis of UG and Abi RTs, increasing the number of UG/Abi members up to 42 highly diverse groups, most of which are predicted to be functionally associated with other gene(s) or domain(s). Based on this information, we classified these systems into three major classes. In addition, we reveal that most of these groups are associated with defense functions and/or mobile genetic elements, and demonstrate the antiphage role of four novel groups. Besides, we highlight the presence of one of these systems in novel families of human gut viruses infecting members of the Bacteroidetes and Firmicutes phyla. This work lays the foundation for a comprehensive and unified understanding of these highly diverse RTs with enormous biotechnological potential.

Prognostic value of microvascular invasion in predicting survival in renal cell carcinoma

OBJECTIVE

To assess microvascular tumor invasion and other clinical and histological parameters as potential prognostic factors in surgically treated renal cell carcinoma.

MATERIALS AND METHODS

Surgical specimens from 238 consecutive patients who underwent radical or partial surgery between 1990 and 2006 were retrospectively evaluated. The series included clinically localized or metastatic renal cell carcinoma (pT1-4; N0-1; M0-1). Disease-free and cancer-specific survival assessments were the end points with median follow-up of 75 months (range 1-189 months). Variables studied included: age, sex, tumor size, TNM 2010 classification, Fuhrman grade, histological subtype and microvascular tumor invasion.

RESULTS

Microvascular tumor invasion was observed in 79 patients (33,2%) and was significantly associated with age (P=.010), tumor size (P=.000), Fuhrman grade (P=.000), pT stage 2010 (P=.000),N stage 2010 (P=.000) and M stage 2010 (P=.000). Multivariate analyses determined that sex, Fuhrman grade, pT stage 2010 and histological subtipe were independent prognostic factors of disease-free survival, while sex, Fuhrman grade, pT stage 2010, M stage 2010, histological subtype and microvascular invasion were prognostic factors for cancer-specific survival.

CONCLUSIONS

Our study shows that microvascular tumor invasion is an independent prognostic factor for cancer-specific survival in surgically treated patients with renal cell carcinoma.

Intraoperative Frozen Section Diagnosis in Urological Oncology

The intraoperative frozen sections are indicated if the pathological findings change the surgical procedure. In urological oncology is not recommended, as a general attitude, in the tumor diagnosis/staging during the surgery. The assessment of the surgical margins is recommended in partial surgical resections but the literature discourages its systematic use in the radical surgical resections. The assessment of the lymph nodes is specially indicated in the penile cancer with intermediate or high risk and non-palpable nodes, and is debated its utility in non-palpable lymph nodes of cystectomies and prostatectomies.

Nuclear volume estimates in prostatic atypical adenomatous hyperplasia

OBJECTIVE

To investigate nuclear volume estimates by the point-sampled intercepts method in atypical adenomatous hyperplasia (AAH) as compared with nodular hyperplasia and well-differentiated prostatic adenocarcinoma.

STUDY DESIGN

The study group consisted of 27 formalin-fixed, paraffin-embedded, whole-mounted radical prostatectomy specimens that contained foci of nodular hyperplasia, atypical adenomatous hyperplasia and well-differentiated adenocarcinoma (Gleason pattern 1 and 2). Representative sections were selected for stereologic estimation of volume-weighted mean nuclear volume by the point-sampled intercepts method. On each focus, an average of five fields of vision were systematically chosen.

RESULTS

The quantitative results indicate an increase in nuclear volume from nodular hyperplasia (209 +/- 65 micron 3) to AAH (237 +/- 85 micron 3) and prostate adenocarcinoma (436 +/- 106 micron 3). Significant differences were found (F = 39.0, P < .001) with two group comparisons (Scheffe's procedure) between prostate cancer and AAH (P < .001) or nodular hyperplasia (P < .001). The difference between AAH and benign hyperplasia was not signifcant.

CONCLUSION

The results indicate that three-dimensional estimates of the nuclear size discriminate AAH and nodular hyperplasia from well-differentiated prostate adenocarcinoma. These findings suggest that AAH is probably a histologic variant of benign prostatic hyperplasia the exact relationship of which to prostatic adenocarcinoma remains to be determined.

[Molecular biology in bladder cancer]

Progress of molecular biology with regard to etiopathogeny of tumours in general, and cancer of the bladder in particular, is taking place at such a vertiginous pace that practising urologists find themselves overwhelmed in terms of their ability to learn and keep updated in so complex a subject. The understanding of certain molecular factors with critical influence on the formation, growth and progression of a tumour of the bladder, is forcing us to make unbiased assessments on the role they will play in the evolution and survival of this neoplasia. It is anticipate they will be much more reliable than traditionally established morphological factors such as grade and stage. We also include a literature review with an analysis and elucidation of the role played by oncogenes, tumor suppressor genes, vascular density markers, telomerase etc., in the formation and growth of cancer of the bladder and their likely relationships with already established clinico-pathological factors.

Nuclear volume estimates in prostatic intraepithelial neoplasia

OBJECTIVE

Prostatic intraepithelial neoplasia (PIN), the most likely precursor of prostatic adenocarcinoma, is divided into two grades, low and high. Pathologists may encounter difficulties in applying these criteria in daily practice. In view of the clinical significance of high grade PIN as strong predictor of carcinoma, the separation of low and high grade PIN plays an important role in patient management. The aim of the present study was to evaluate three-dimensional nuclear size estimation in normal prostatic glands, low and high grade PIN, and prostatic adenocarcinoma as an element in their classification.

STUDY DESIGN

We studied 31 formalin-fixed, paraffin-embedded, whole-mounted radical prostastectomy specimens that contained foci of normal prostatic glands, low and high grade PIN, and prostatic adenocarcinoma. Hematoxylin-eosin-stained sections were selected for the stereologic estimation of volume-weighted mean nuclear volume by the "point-sampled intercepts" method. On each focus, an average of six fields of vision were systematically chosen.

RESULTS

The quantitative results indicate a significant increase in nuclear volume from normal prostatic glands (mean, 209.0 micron 3; SD, 64.6 micron 3) to low grade PIN, high grade PIN and prostatic adenocarcinoma with increments of 49%, 88% and 109%, respectively (F = 29.1, P < .001). Two-group comparisons (Duncan procedure) showed differences between low and high grade PIN and prostatic adenocarcinoma (P < .01). The difference between high grade PIN and prostatic adenocarcinoma was not significant.

CONCLUSION

Three-dimensional estimates of nuclear size discriminate low and high grade PIN. Lack of stereologic differences between high grade PIN and prostatic adenocarcinoma further supports high grade PIN as a precursor of prostatic adenocarcinoma.

Virilizing mature ovarian cystic teratomas

Three further cases of mature benign cystic teratomas of the ovary associated with virilization are added to the three previously reported in the literature. They were found in postmenopausal, obese, diabetic women aged 52, 61, and 67 years. The patients presented with hirsutism and voice changes and clitoromegaly was present in one. Testosterone and androstenedione levels were elevated but promptly regressed after removal of the tumours. Histologically, sheets of stromal luteinized cells were found peripherally at the interface between the neoplasm and ovarian tissue. Luteinization of ovarian stroma induced by an unknown factor related to diabetes mellitus is the origin of the virilization.

Lipomatous hypertrophy of the cardiac interatrial septum

A case of lipomatous hypertrophy of the cardiac interatrial septum is reported in a 91-year-old man who attempted to commit suicide. The lesion was found incidentally at autopsy. Gross examination showed a 3.5-cm mass, yellow and firm. Histologic study showed a proliferation of mature fat cells and slightly hypertrophic cardiac muscle cells.

Quantitative histopathologic discrimination of rheumatic disorders using nuclear measurements of synoviocytes

OBJECTIVE

To use several nuclear quantitative estimators of synoviocytes and advanced statistical tests to discriminate between rheumatic disorders with the purpose of providing an objective histopathologic differentiation and to illustrate the difficulty of establishing the implications of the vague diagnosis of chronic nonspecific synovitis.

STUDY DESIGN

Synovial histologic material from 48 patients, including a control group and those diagnosed with osteoarthritis, rheumatoid arthritis and chronic nonspecific synovitis, was analyzed. Both morphometric and stereologic nuclear measurements were assessed in each case, and several stepwise discriminant analyses were performed to obtain linear discriminant functions.

RESULTS

Differences in the nuclear size parameters were found between rheumatoid arthritis and the normal and osteoarthritis groups and between normal and chronic nonspecific synovitis. The volume-weighted mean nuclear volume was the most significant parameter. No differences were demonstrated between osteoarthritis and normal and chronic nonspecific synovitis or between rheumatoid arthritis and chronic nonspecific synovitis except for nuclear volume. Using stepwise discriminant analysis, 94% of the cases were correctly classified when differentiating the normal, osteoarthritis and rheumatoid arthritis groups. The overall accuracy of diagnosis decreased to 83% when chronic nonspecific synovitis samples were included. The misclassified samples were related mainly to normal cases and to osteoarthritis and chronic nonspecific synovitis cases.

CONCLUSION

This study emphasized that nuclear quantitative features of synoviocytes may be useful in differentiating rheumatic disorders objectively, especially in combination with discriminant analysis. Thus, nuclear changes in the synovium in chronic nonspecific synovitis show a closer similarity to normal and osteoarthritis than to rheumatoid arthritis.

Specific monoclonal antibodies against leukocyte-restricted cell surface molecule CD43 react with nonhematopoietic tumor cells

CD43 is the major sialoglycoprotein found on the surface of cells of hemopoietic origin. Because CD43 is a typical member of the surface mucins, molecules that play a relevant role in tumor progression, we have addressed the expression of CD43 in nonhematopoietic tumor cells. For this purpose, we have tested a broad panel of anti-CD43 antibodies on tumors of different embryonic origins. Of the 17 anti-CD43 mAbs used, 9 reacted with leukocytes in paraffin-fixed formalin-embedded lymph node tissues. Two mAbs, BS1 and L10, stained 24 out of 31 (78%) nonhematopoietic tumors analyzed; ie., some tumors were positive for both antibodies, and others were positive for either L10 or BSL We have also found reactivity of these two anti-CD43 mAbs in 13 out of 20 metastases studied.

Human papillomavirus infection and transitional cell carcinoma of the bladder. Immunohistochemistry and in situ hybridization

The aim of the present research was to investigate human papillomavirus (HPV) infection by means of immunohistochemistry and in situ hybridization in 76 bladder cancer specimens. A biotinylated DNA probe that recognizes HPV 6/11, HPV 16/18 and HPV 31/33/35 was used for in situ hybridization. A polyclonal antibody recognizing HPV capsid antigen (HPVcAg) was used for immunohistochemistry. In situ hybridization and immunohistochemistry were developed by alkaline phosphatase and immunogold-silver techniques respectively. Our results showed that 25 (32.8%) out of 76 bladder carcinoma specimens reacted with HPVcAg. Twelve (15.7%) out of 76 cases were positive for HPV 16/18-DNA using non-isotopic in situ hybridization. Sixteen cases had koilocytosis. No positive signals were found for HPV 6/11 or 31/33/35-DNA probes.

Stereological analysis of the synovial membrane in rheumatic disorders: diagnostic value of volume-weighted mean nuclear volume estimation

Quantitative evaluation of nuclear size of synoviocytes was performed on 48 synovial biopsies in various rheumatic disorders: osteoarthritis (n = 10), rheumatoid arthritis (11), and chronic non-specific synovitis (14). Thirteen tissue specimens from non-inflammatory synovial membrane were included as a control group. Using the point-sampled intercepts method, unbiased stereological estimates of volume-weighted mean nuclear volume (nuclear upsilon v) were obtained. A slight increase in nuclear volume was observed in osteoarthritis in comparison with the control group with an overlap in 90% of cases. However, in rheumatoid arthritis there was a significant increase of nuclear upsilon v. Significant differences were found between rheumatoid arthritis and the control and osteoarthritis groups (P < or = 0.001). In biopsies from patients diagnosed as chronic non-specific synovitis the averaged nuclear upsilon v values were between those in osteoarthritis and rheumatoid arthritis with a wide range of data. Similar, but less significant differences were demonstrated between rheumatic disorders when using mean nuclear area. Further analysis of chronic non-specific synovitis patients in combination with nuclear upsilon v estimates as a simple, unbiased, complementary tool are required to better establish the diagnostic value of nuclear stereology in the diagnosis of rheumatic disorders.

Visceral Kaposi's sarcoma without mucocutaneous involvement in a heart transplant recipient

Kaposi's sarcoma has been occasionally reported in heart transplant recipients, but its occurrence without mucocutaneous involvement is extremely rare. In these uncommon cases, the tumor can be indistinguishable from opportunistic infections, making diagnosis difficult. The case of a patient in whom visceral Kaposi's sarcoma was diagnosed by necropsy 6 months after heart transplantation is reported.

Hyaline globules in uterine malignant mixed müllerian tumours. A diagnostic aid?

In order to evaluate the presence of hyaline globules (HGs) in uterine malignant mixed müllerian tumours (MMMT), and its possible diagnostic value in haematoxylin & eosin stained sections, a retrospective microscopic study of 38 cases (13 homologous and 25 heterologous) was carried out. Intra- and extracellular HGs were found in 31 MMMT (81.6%), 8 homologous (61.5%) and 23 heterologous (92%). In addition, strong alpha-1-antitrypsin immunoreactivity was also noted in the HGs of 10 cases out of 13 investigated. In initial diagnostic curettage material, HGs were observed in 18 of 22 cases (81.8%), 6 of 9 homologous (66.7%) and 12 of 13 heterologous (92.3%). In view of the high incidence of HGs in curettage specimens, their finding in haematoxylin & eosin stained sections could orientate a histopathologic preoperative diagnosis of MMMT, specially of heterologous type, and may be considered a diagnostic tool in order to indicate an early, planned therapy and staging in these neoplasms of poor prognosis.

Squamous and glandular differentiation in urothelial bladder carcinomas. Histopathology, histochemistry and immunohistochemical expression of carcinoembryonic antigen

This paper reports the immunochemical expression of carcinoembryonic antigen in the squamous, glandular and mixed differentiation areas observed in 190 urothelial urinary bladder carcinomas. The antigen was found to occur in 75% and 81% of all papillary and solid infiltrating carcinomas, respectively. The use of the immunohistochemical determination of CEA in improving the morphological examination of these differentiation areas and their scant presence in the prognosis of urothelial carcinomas involving squamous and/or glandular focal differentiation are discussed.

[Projections of the nucleus praepositus hypoglossi to the cerebellum in the cat]

The axonal projections from the nucleus praepositus hypoglossi (PH) to the cerebellum have been studied in cat. Cerebellar projections were evidenced by means of the retrograde axonal transport of horseradish peroxidase. According to the results the PH nucleus projects to the entire vermis, especially to the posterior lobes, as to the flocculus and paraflocculus. No projections to other areas of the cerebellar cortex were found. PH projections go to the cerebellum through the inferior peduncle.

A morphological and electrophysiological study of nigrotectal pathway in the rat

After horseradish peroxidase injections in the superior colliculus of the rat, labelled cells were found in the pars reticulata of the substantia nigra. Nigrotectal cells are organized in a band beginning in the ventromedial area of the rostral part of pars reticulata, while at caudal levels they occupy a more lateral position, closely packed near the cerebral peduncle. In another series of experiments, the effects of substantia nigra electrical stimulation on collicular unitary activity was studied in anaesthetized rats. Electrical stimulation of the substantia nigra decreased the spontaneous and pharmacologically induced activity of superior colliculus neurons. Inhibition took place with short latencies (1-4 msec). Inhibited cells were localized in deep layers of the superior colliculus. In addition, long latency activation and inhibition were also obtained. It is concluded that nigrotectal pathway is mainly inhibitory in character.